<script setup>
import { ref } from 'vue';
import { useMouseInElement } from '@vueuse/core';
import { watch } from 'vue';
defineProps({
  imageList:{
    type: Array,
    default: ()=>[]
  }
})

const activeIndex = ref(null)
// 鼠标移入小图回调
const mouseEnter = (i)=>{
  activeIndex.value = i
}
//获取鼠标的相对位置
const target = ref(null)
const { elementX,elementY,isOutside} = useMouseInElement(target)

//控制滑块跟随鼠标移动，监听elementX/Y变化，一旦变化，重新设置left/top
const left = ref(0)
const top = ref(0)
const positionX = ref(0)
const positionY = ref(0)
watch([elementX , elementY],()=>{
  //如果鼠标未移入盒子，下列逻辑不执行
  if(isOutside.value) return
  //有效范围控制滑块距离
  //横向
  if(elementX.value>100 && elementX.value<300){
    left.value = elementX.value - 100
  }
  //纵向
  if(elementY.value > 100 && elementY.value<300){
    top.value = elementY.value - 100
  }
  //处理边界
  if(elementX.value > 300){left.value = 200}
  if(elementX.value < 100){left.value = 0}

  if(elementY.value > 300){top.value = 200}
  if(elementY.value < 100){top.value = 0}

  positionX.value = -left.value*2
  positionY.value = -top.value*2
})

</script>
<template>
  <div class="goods-image">
    <!-- 左侧大图 -->
    <div class="middle" ref="target">
      <img :src="imageList[activeIndex]" alt="">
      <!-- 蒙层小滑块 -->
       <div class="layer" :style="{left:`${left}px` , top:`${top}px`}"></div>
    </div>
    <!-- 小图列表 -->
     <ul class="small">
      <li v-for="(img , i) in imageList" :key="i" @mouseenter="mouseEnter(i)" :class="{ active: activeIndex === i }">
        <img :src="img" alt="">
      </li>
     </ul>
     <!-- 放大镜大图 -->
      <div class="large" :style="
      [
        {
        backgroundImage: `url(${imageList[activeIndex]})`,
        backgroundPositionX:`${positionX}px`,
        backgroundPositionY: `${positionY}px`,
        }
      ]
      " v-show="!isOutside"></div>
  </div>
</template>

<style scoped lang="scss">
.goods-image{
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  .middle{
    width: 400px;
    height: 400px;
    background: #f5f5f5;
  }
  .large{
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    z-index: 500;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    //背景图：盒子的大小=2 ：1 将来控制背景图的移动来实现放大的效果查看 background-position
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }
  .layer{
    width: 200px;
    height: 200px;
    background: rgba(0, 0, 0, 0.2);
    // 绝对定位 然后跟随咱们鼠标控制left和top属性就可以让滑块移动起来
    left: 0;
    top: 0;
    position: absolute;
  }
  .small{
    width: 80px;
    li{
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;
      &:hover
      ,
      &.active{
        border: 2px solid $xtxColor;
      }
    }
  }
}
</style>
